Xanthomonas albilineans Haplotype B Responsible for a Recent Sugarcane Leaf Scald Disease Outbreak in Cuba

Over the past 3 years, the incidence of sugarcane leaf scald disease (LSD) caused by Xanthomonas albilineans has increased at alarming rates in some Caribbean countries. LSD was in latent phase since 1978, when the disease was reported in Cuba, until February 1998 when typical symptoms were observed in germ plasm collections and in some commercial plantings. More than 150 bacterial isolates from different sugarcane varieties and from different localities were isolated on Wilbrink agar medium and characterized. All isolates had shown similar cultural and biochemical patterns. However, serological differences between isolates from the recent outbreak and the ones obtained prior to 1998 were detected by indirect ELISA testing. Differences between Cuban isolates obtained prior to 1998 and those from the recent outbreak were confirmed by analysis of repetitive DNA sequences dispersed throughout the genome. According to the pattern obtained, the newer isolates were similar to reference strains classified as haplotype B by pulsed field gel electrophoresis (1). It is concluded that the recent outbreak of LSD was caused by a strain different than the ones previously detected in Cuba. Reference: (1) M. J. Davis et al. Phytopathology 87:316, 1997.